Hi Clo:
Yes it is, hence it's current strength. We must take care in defending its status.
The possibility of China and India trading for Iranian oil in gold, rupees and yuans, or barter could further erode the dollar's international role. Don't want to get a ball rolling. The U.S. is pressing hard to get India, China, and Japan to reduce oil imports from Iran, with some success.
Iran is such a wild card in today's teeter-totter environment. The upcoming EU oil embargo should do wonders for Europe. Maybe a nice recession will reduce demand.